Valco Cincinnati VC3500, User Manual

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Appendix B
VC3700 User’s Manual
Valco Cincinnati
89
Note! The Visual Basic “Chr$” function returns a one-character string whose ANSI code is the argument.
Distance-type data in inch units assume two decimal places. Therefore, if 0,1,0,0 were sent, either 01.00 inches or
0100mm would be specified, depending on the inch/metric setting of the control. Time-type data (in milliseconds)
assume one decimal place. Therefore, if 0,0,5,5 were sent, 005.5 ms would be specified. Data for ratio compensa-
tion (in pulses per inch) also use one decimal place.
Sending Information from Host to VC3700
Information may only be sent or received by the control if the main screen (the screen containing the pressure bar
graph) is visible. Data can be sent or received while the control is gluing. However, the programmer must take care
not to leave the data partly sent, since the control will appear to lockout the touch screen and minimum speed
detection! This can leave the control open to undesirable effects. It is possible to regain control from this situation
by sending groups of at least six zeros to the control from the host, but it is always better to send or receive the
complete data format.
Transfer of information uses the following format at 9600 baud, no parity, 8 data bits and 1 stop bit:
1. Send send-request byte from host.
Send-request byte = 254dec.
2. Receive ACK (acknowledge) byte from VC3500/3700.
This indicates that the control will start looking for the data. After the request byte is received, the control
returns ACK (255dec). If this byte is not returned after 500ms, the host must terminate the send.
3. Send byte 4, byte 3, byte 2, byte 1, location code from host.
Byte 4=Msb and byte 1=Lsb.
Note! If the command is sent to redraw the front screen, the ACK signal can take up to 2 seconds to
respond.
Example of Sending Data
Example:
Channel 1—Delay length = 100mm (1.00 inches)
Channel 1—Pattern length = 100mm (1.00 inches)
To send this information, follow these steps:
1. Send 254.
2. Wait for ACK.
3. Send 0,1,0,0,1.
4. Send 254.
5. Wait for ACK.
6. Send 0,1,0,0,2.
The front screen needs to be redrawn only after all the pattern data is sent, and only if the screen that the data is
referenced to is visible. The control will respond to new data and update the glue line automatically upon reception
of each new data packet, regardless of the information displayed by the screen.
It is better to send the redraw command after all of the data is transferred to the control, so that the data is sent at
maximum speed. Timing problems may be encountered if attempts are made to redraw the screen after each send. If
redrawing the screen after each send is required, a two-second delay (waiting for ACK) must be allowed for the
redraw to take place.